(1) Field of the Invention
The present invention pertains to an assembly that is used to adapt a BNC type connector of a microsurgical optic fiber instrument to a threaded SMA type bushing connector of a light source.
(2) Description of the Prior Art
In microsurgery such as ophthalmic surgery or surgery of the eye, various different types of instruments are available for use by the surgeon to deliver light to the interior of the eye. These instruments deliver light for illumination as well as laser light for use in surgery. A basic microsurgical instrument of this type is comprised of a handle with a projecting tubular probe or tip and a length of optic fiber entering the rearward end of the handle and passing through the handle and the tip to the tip distal end. The proximal end of the optic fiber opposite its connection to the handle is provided with a connector for connecting the fiber proximal end to a light source, either an illumination source or a laser light source. By positioning the proximal end of the optic fiber adjacent the light source, the light is transmitted through the fiber to its distal end and is emitted from the distal end. Where the light source is a source of laser light used in eye surgery, the positioning of the fiber proximal end relative to the laser light must be accurately controlled. Connectors employed for such a purpose are referred to as SMA type connectors.
FIGS. 1 and 2 show examples of prior art SMA connectors with FIG. 1 illustrating the construction of a male optic fiber connector and FIG. 2 illustrating the construction of a female optic fiber connector. These prior art connectors are widely used and will only be described generally.
The female connector or bushing 12 is provided with an alignment sleeve 18 in its interior that ensures a precise alignment of an optic fiber (not shown) extending through the male connector 10 along the male connector center axis 14. A laser light source is positioned relative to the female connector 12 to direct a beam of laser light along the female connector center axis 16. The female connector has a first set of external screw threading 20 that is employed in securing the female connector 12 to a wall or bracket of the laser light source to securely hold the female connector relative to the light source. A second set of external screw threading 22 on the female connector is employed in attaching the male connector 10 to the female connector.
The male connector 10 includes a center ferrule 24 on which a cable nut 26 is mounted for rotation. The cable nut 26 is secured on the ferrule 24 by a back post 28 that is screw threaded on the ferrule. The cable nut 26 has internal screw threading 30 that is complementary to the external screw threading 22 of the female connector. The optic fiber of the microsurgical instrument (not shown) passes through the back post 28 and the ferrule 24 with a distal end of the optic fiber being positioned adjacent the distal end of the ferrule 24.
In attaching the male connector 20 to the female connector 12, the ferrule 24 is first inserted through the interior bore of the female connector and into the alignment sleeve 18. The cable nut 26 is turned causing its internal threading 30 to be screw threaded onto the external threading 22 of the female connector and to securely connect the male connector 10 with the female connector 12 with their respective axes aligned. In this way, the beam of laser light of the light source (not shown) is directed at the exposed end of the optic fiber contained in the male connector 10.
Use of the prior art connectors described above has been found to be inconvenient in that it is necessary to completely unscrew the cable nut 26 of the male connector 10 from the external screw threading 22 of the female connector 12 when removing one instrument from the light source and then screw a cable nut 26 of another instrument onto the female connector external threading 22 when switching one microsurgical instrument for another. It would be more convenient if the male connector 10 could be quickly connected with and disconnected from the female connector 12 without requiring repeated rotations of a cable nut in connecting and disconnecting the two connectors.
The prior art also includes laser light sources having female connectors 12 and sets of microsurgical instruments having male connectors 10 that can only be used with each other. This has been found to be inconvenient when it is desirable to use other types of microsurgical instruments with the particular laser light source. The prior art laser light source is specifically designed so that it will not operate if a male connector of a microsurgical instrument is connected to the light source where the microsurgical instrument and male connector are not manufactured by the particular manufacturer of the light source. This is accomplished by encoding the male connector 10 of the surgical instrument with an electronic device that is recognized by the light source when the male connector is attached to the female connector of the light source. An example of such a male connector and female connector is disclosed in the U.S. Pat. No. 5,085,492 of Kelsoe et al.
The above-described inconvenience could be overcome by an adapter that can be attached to the female connector of a laser light source of the type that operates only with associated electronically encoded surgical instruments where the adapter contains the electrical device recognized by the light source and also enables a quick connect and disconnect of the surgical instrument to the adapter.
The present invention overcomes the inconveniences of prior art SMA type connectors described above by providing an adapter that enables a BNC type connector to be attached to the external screw threading of a female connector or bushing of the SMA type. In addition, the adapter also is electronically encoded and therefore enables use of any type of surgical instrument having a BNC type connector with a laser light source of the type that only recognizes electronically encoded surgical instruments.
The adapter of the invention is part of an assembly that includes a microsurgical optic fiber instrument having a BNC type connector in lieu of a SMA type connector usually found on these types of surgical instruments. Like the SMA connector, the BNC connector also has a center ferrule that projects from the connector and through which the optic fiber extends. However, instead of having the cable nut found on SMA connectors, the BNC connector of the invention has a conventional BNC type connector including a cylindrical collar with a pair of spiraling slots formed in the collar.
The adapter includes a cylindrical adapter sleeve constructed of a conductive material, preferably metal. The sleeve has an external surface with a pair of posts projecting from the surface on diametrically opposite sides of the sleeve. The posts are positioned to be engaged by the slots of the BNC connector to enable the BNC connector to be attached to the exterior surface of the sleeve by merely turning the BNC connector one quarter turn relative to the sleeve. The sleeve also has a cylindrical interior surface and a cylindrical insulator is secured inside the sleeve. In one embodiment of the adapter the insulator does not extend through the entire length of the sleeve but is only positioned adjacent the end of the sleeve to be attached to the externally threaded female bushing of the laser light source of the type described earlier. The insulator has internal screw threading that is complementary to that of the female bushing of the laser light source. Screwing the insulator threading onto the external threading of the light source female bushing attaches the sleeve to the light source female bushing but insulates the conductive material of the sleeve from that of the bushing.
An annular conductive stop is also secured in the interior of the adapter sleeve. The stop is positioned in the adapter sleeve where it will come into electrical contact with the female bushing of the laser light source when the adapter sleeve is attached to the female bushing.
An electrical device is also secured to the interior of the adapter sleeve. The electrical device is connected electrically between the annular stop and the interior surface of the sleeve, thus establishing a circuit path from the annular stop to the sleeve through the electrical device.
A second, preferred embodiment of the adapter also includes the cylindrical adapter sleeve having an external surface with a pair of posts projecting from the surface as in the first embodiment. The posts are positioned to be engaged by the slots of the BNC connector as in the first embodiment. The sleeve has a cylindrical interior surface. The sleeve of the second embodiment differs from that of the first embodiment in that at least one of the sleeve posts has an internally threaded bore extending entirely through the post from the exterior of the sleeve to the interior of the sleeve.
A cylindrical insulator is secured inside the sleeve bore. The insulator differs from that of the first embodiment in that it extends entirely through the length of the sleeve. A hole is provided through the insulator and is aligned with the threaded interior bore of the sleeve post.
A conductive cylindrical insert is provided in the interior bore of the insulator. The insulator separates and insulates the insert from the sleeve. The insulator has internal screw threading that is complementary to that of the female bushing of the laser light source. The internal screw threading does not extend through the entire length of the insert, but is only positioned adjacent the end of the insert to be attached to the externally threaded female bushing of the laser light source. An annular conductive stop is also secured in the interior of the insert. The stop is positioned at the end of the insert internal screw threading where it will come into electrical contact with the female bushing of the laser light source when the adapter sleeve is attached to the female bushing.
An electrical device is also secured to the interior of the adapter sleeve. However, in this embodiment the electrical device is positioned inside the sleeve post interior bore and is connected electrically between the conductive insert and the sleeve post, thus establishing a circuit path from the insert to the sleeve through the electrical device. In both embodiments of the adapter, the electrical device is preferably a resistor. However, other electrical devices as well as combinations of electrical devices may be employed in lieu of the resistor.
In use of either of the embodiments of the assembly, the adapter sleeve is first attached to the external threading of the laser light source female bushing by screw threading the insulator of the first embodiment or the insert of the second embodiment onto the female bushing until the end of the female bushing comes into contact with the annular stop inside the sleeve. This establishes a circuit path from the female bushing through the electrical device and the conductive sleeve of the adapter. With the adapter attached to the female bushing of the laser light source, any optic fiber microsurgical instrument having the BNC connector of the invention may be easily connected and disconnected from the laser light source by turning the BNC connector one quarter turn relative to the adapter attached to the laser light source.
When the BNC connector of the surgical instrument is attached on the adapter, an electric circuit is established from the female bushing of the laser light source through the electrical device, the adapter and now the collar of the BNC connector. The prior art laser light source discussed above also includes an external contact that is positioned to come into contact with the cable nut of a conventional SMA type connector when attached to the female bushing of the light source. This external contact comes into contact with the BNC connector of the assembly and thereby a complete electrical circuit is established from the female bushing of the light source through the electrical device of the adapter and through the BNC connector and the external contact of the light source.
The electrical device, for example the resistor referred to, is specifically chosen to make either adapter compatible with the particular light source. When the electric circuit discussed above is established by connecting the adapter and BNC connector of the invention with the female bushing of the light source, the light source recognizes the particular electrical device provided in the adapter. Thus, the laser light source will operate as though an SMA connector manufactured by the same manufacturer of the light source was connected to the female bushing of the light source.
Thus, the assembly of the invention including the adapter and the BNC connector enables a quick connect and disconnect of the surgical instrument with the laser light source and also enables surgical instruments to be employed with the particular light source that were not manufactured by the particular manufacturer of the light source.